Process of removing and recovering tin.



JULIUS ELKES, OF MOUNT PLEASANT, PENNSYLVANIA.

PROCESS OF REMOVING AND REGOVERING TIN.

Specification of Letters Patent.

Patented April 27, 1909.

Application filed January 22, 1909. Serial No. 473,755.

In carrying my process into practice, I'

first make a solution of ammonium sulfid (NH ),S, and add enough free sulfur to convert the tin into a solution of tin-sulfid;

The metal from which the tin is to be recovered is, in suitable form, placed in this bath of solution, after which sufficient water is added and the bath boiled until all the tin is removed and in solution. The metal which is now clean from tin is removed from the bath and a suitable amount of hydrochlorid acid is then added to the bath to precipitate the tin as tin sulfid, the latter being filtered to separate the precipitate:

The H S gas evolved during the-addition of the hydrochloric acid to the bath is introduced into fresh ammonia water to obtain a new solution of ammonium sulfid for further use. chlorid with some sulfur is allowed to stand until the excess of sulfur is settled, whereupon it is filtered and evaporated to dryness to recover the crystallized salt ammonium chlo-.

rid. This recovery .of a commercial product.

tends, of course, to cheapen the cost of the 'lhebath which contains ammonium process as a whole. After drying the tin sulfid precipitate is roasted to drive 0d the sul ur and convert it into tin dioxid sns,+o, =sno 2e0 and then this dioxid of tin is mixed with coal or anequivalent carbonaceous substance and some flux, as limestone or the like, to reduce it to metallic tin:.SnO -|-2C=Sn+2CO. This process of treatment is exceedingly simple and effective, and by'its use tin from old tinware, tin plate, and scrap material may be recovered at a low cost.

I claim 1. The herein-described process of recovering tin from old and scrap materials, which consists in converting the tin into a tin sulfid, then converting it into a tin dioxid, and then reducing the tin dioxid with a carbonaceous substance.

2. The herein-described process of recov ering tin from old and scrap materials, which consists in converting the tin into a tin suhid,

- then converting it into a tin dioxid and then reducing the tin dioxid with coal.

3. 'lhe herein-described process of recovermg t1n from old and scrap materials, whlch consists in immersing the material 1n an ammonlum sulfid bath containing an excess of sulfur, heating the bath until the tin 18 removed and converted into a tin sulhd, mtro- 'ducing hydrochloric acid to precipitate the tin sulfid, heating the precipitate to drive oil the sulfur and convert-it into tin dioxid, and then reducing the dioxid with a carbonaceous substance, such as coal.

In testimony whereof I afl'ix my sigi'iature in presence of two witnesses.

JULIUS ELKES.

Witnesses:

NATHAN ABnAMsoN, DAVID SILVERMAN. 

